Which of the following is NOT one of the three major assumptions that underpin the concept of a 'contract of employment'

• A. that the relationship between employer and employee is an individual one, made between two parties of equal bargaining strength
• B. that there is an imbalance of power between the two parties
• C. it consists of a promise to work (or be available for work) for which payment is promised
• D. since there has been a free exchange of promises, the two parties have reciprocal, but different rights and obligations